Calyx nicaensis Calysterol

Calysterol (25) is a C29 cyclopropene-containing marine sterol isolated from the sponge Calyx nicaensis. The presence in calysterol of a cyclopropene ring suggests that in marine organisms sterols with unusual side chains may be quite widespread. 

Other biogenetically distinct cyclopropane side chain substitution patterns are typified by the sponge sterols calysterol (25) isolated from Calyx nicaensis, and petrosterol (19) found in Petrosia. Unlike the biosynthesis of gorgosterol-type (17)... 

An extract of Calyx nicaensis has provided the three biologically active cyclopropene-containing marine sterols (28R)-calysterol (4), (23R)-23H-isocalysterol (5) and (24S)-24H-isocalysterol (6) " Whilst calysterol (4) is the major isomer and the first of the series to... 

Fattorusso, E., Magno, S Mayol, L Santacroce, C and Sica, D. (1975a) Calysterol, a C29 cydopropene-containing marine sterol from frie sponge Calyx nicaensis. Tetrahedron, 31,1715-1716. 

A new remarkable side chain alkylation pattern has been found in calysterol, the principal sterol component of the sponge Calyx nicaensis 75a). Structure (181), reminiscent of those of gorgosterol (175) and its relatives (176) and (177), has been proposed for this unique sterol on the basis of spectral data (m.s. and n.m.r.) of the acetate, m.p. 105—106°, [a]o-34.3°, and Lemieux oxidation of the corresponding stanol to a p-diketone (182). Interestingly, calysterol (181) completely decomposes on an alumina-silver nitrate column to give four compounds the major one has been characterized as (182 a). 

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